Displaying publications 81 - 100 of 160 in total

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  1. Mechanisms of Blood Brain Barrier Disruption by Different Types of Bacteria, and Bacterial-Host Interactions Facilitate the Bacterial Pathogen Invading the Brain
    Al-Obaidi MMJ, Desa MNM
    Cell Mol Neurobiol, 2018 Oct;38(7):1349-1368.
    PMID: 30117097 DOI: 10.1007/s10571-018-0609-2
    This review aims to elucidate the different mechanisms of blood brain barrier (BBB) disruption that may occur due to invasion by different types of bacteria, as well as to show the bacteria-host interactions that assist the bacterial pathogen in invading the brain. For example, platelet-activating factor receptor (PAFR) is responsible for brain invasion during the adhesion of pneumococci to brain endothelial cells, which might lead to brain invasion. Additionally, the major adhesin of the pneumococcal pilus-1, RrgA is able to bind the BBB endothelial receptors: polymeric immunoglobulin receptor (pIgR) and platelet endothelial cell adhesion molecule (PECAM-1), thus leading to invasion of the brain. Moreover, Streptococcus pneumoniae choline binding protein A (CbpA) targets the common carboxy-terminal domain of the laminin receptor (LR) establishing initial contact with brain endothelium that might result in BBB invasion. Furthermore, BBB disruption may occur by S. pneumoniae penetration through increasing in pro-inflammatory markers and endothelial permeability. In contrast, adhesion, invasion, and translocation through or between endothelial cells can be done by S. pneumoniae without any disruption to the vascular endothelium, upon BBB penetration. Internalins (InlA and InlB) of Listeria monocytogenes interact with its cellular receptors E-cadherin and mesenchymal-epithelial transition (MET) to facilitate invading the brain. L. monocytogenes species activate NF-κB in endothelial cells, encouraging the expression of P- and E-selectin, intercellular adhesion molecule 1 (ICAM-1), and Vascular cell adhesion protein 1 (VCAM-1), as well as IL-6 and IL-8 and monocyte chemoattractant protein-1 (MCP-1), all these markers assist in BBB disruption. Bacillus anthracis species interrupt both adherens junctions (AJs) and tight junctions (TJs), leading to BBB disruption. Brain microvascular endothelial cells (BMECs) permeability and BBB disruption are induced via interendothelial junction proteins reduction as well as up-regulation of IL-1α, IL-1β, IL-6, TNF-α, MCP-1, macrophage inflammatory proteins-1 alpha (MIP1α) markers in Staphylococcus aureus species. Streptococcus agalactiae or Group B Streptococcus toxins (GBS) enhance IL-8 and ICAM-1 as well as nitric oxide (NO) production from endothelial cells via the expression of inducible nitric oxide synthase (iNOS) enhancement, resulting in BBB disruption. While Gram-negative bacteria, Haemophilus influenza OmpP2 is able to target the common carboxy-terminal domain of LR to start initial interaction with brain endothelium, then invade the brain. H. influenza type b (HiB), can induce BBB permeability through TJ disruption. LR and PAFR binding sites have been recognized as common routes of CNS entrance by Neisseria meningitidis. N. meningitidis species also initiate binding to BMECs and induces AJs deformation, as well as inducing specific cleavage of the TJ component occludin through the release of host MMP-8. Escherichia coli bind to BMECs through LR, resulting in IL-6 and IL-8 release and iNOS production, as well as resulting in disassembly of TJs between endothelial cells, facilitating BBB disruption. Therefore, obtaining knowledge of BBB disruption by different types of bacterial species will provide a picture of how the bacteria enter the central nervous system (CNS) which might support the discovery of therapeutic strategies for each bacteria to control and manage infection.
    Matched MeSH terms: Brain/metabolism*
  2. The debate over neurotransmitter interaction in aspartame usage
    Choudhary AK, Lee YY
    J Clin Neurosci, 2018 Oct;56:7-15.
    PMID: 30318075 DOI: 10.1016/j.jocn.2018.06.043
    Aspartame (NutraSweet®, Equal®) is a widely used artificial sweetener, has been reported to be accountable for neurological and behavioural disturbances in people. Upon ingestion, aspartame is hydrolyzed in gut and provides its metabolite; such as essential amino acid phenylalanine (Phy) (50%), aspartic acid (40%), and methanol (10%). Altered brain neurochemical compositions [such as dopamine (DA), norepinephrine (NE), and serotonin (5-HT)] have long been a concern and being involved in observed neurophysiological symptom (such as headaches, memory loss, mood changes, as well as depression) in aspartame consumers. Aspartames might act as chemical stressor through increasing plasma cortisol level. Aspartame consumption similarly altered gut microbiota. Taken together all this factors, we reviewed to search for convincing evidence, in what manner aspartame metabolites, stress hormones (cortisol), and gut dysbiosisis involved in altering brain neurochemical composition. We concluded that aspartame metabolite; mainly Phy and its interaction with neurotransmitter and aspartic acid by acting as excitatory neurotransmitter causes this pattern of impairments. Along with elevated cortisol and gut dysbiosis via interactions with different biogenic amine may also have additional impact to modulate neuronal signaling lead to neurobiological impairments. Hence ongoing research is instantly needed to understand the specific roles of aspartame metabolite, elevated cortisol, and gut dysbiosis with emerging neurophysiological symptom in aspartame consumers to improve healthy life in its consumers.
    Matched MeSH terms: Brain/metabolism
  3. Rate and extent of mitragynine and 7-hydroxymitragynine blood-brain barrier transport and their intra-brain distribution: the missing link in pharmacodynamic studies
    Yusof SR, Mohd Uzid M, Teh EH, Hanapi NA, Mohideen M, Mohamad Arshad AS, et al.
    Addict Biol, 2019 09;24(5):935-945.
    PMID: 30088322 DOI: 10.1111/adb.12661
    Mitragyna speciosa is reported to be beneficial for the management of chronic pain and opioid withdrawal in the evolving opioid epidemic. Data on the blood-brain barrier (BBB) transport of mitragynine and 7-hydroxymitragynine, the active compounds of the plant, are still lacking and inconclusive. Here, we present for the first time the rate and the extent of mitragynine and 7-hydroxymitragynine transport across the BBB, with an investigation of their post-BBB intra-brain distribution. We utilized an in vitro BBB model to study the rate of BBB permeation of the compounds and their interaction with efflux transporter P-glycoprotein (P-gp). Mitragynine showed higher apical-to-basolateral (A-B, i.e. blood-to-brain side) permeability than 7-hydroxymitragynine. 7-Hydroxymitragynine showed a tendency to efflux, with efflux ratio (B-A/A-B) of 1.39. Both were found to inhibit the P-gp and are also subject to efflux by the P-gp. Assessment of the extent of BBB transport in vivo in rats from unbound brain to plasma concentration ratios (Kp,uu,brain ) revealed extensive efflux of both compounds, with less than 10 percent of unbound mitragynine and 7-hydroxymitragynine in plasma crossing the BBB. By contrast, the extent of intra-brain distribution was significantly different, with mitragynine having 18-fold higher brain tissue uptake in brain slice assay compared with 7-hydroxymitragynine. Mitragynine showed a moderate capacity to accumulate inside brain parenchymal cells, while 7-hydroxymitragynine showed restricted cellular barrier transport. The presented findings from this systematic investigation of brain pharmacokinetics of mitragynine and 7-hydroxymitragynine are essential for design and interpretation of in vivo experiments aiming to establish exposure-response relationship.
    Matched MeSH terms: Brain/metabolism
  4. Expression of neuropeptide Y and gonadotropin-releasing hormone gene types in the brain of female Nile tilapia (Oreochromis niloticus) during mouthbrooding and food restriction
    Das K, Ogawa S, Kitahashi T, Parhar IS
    Peptides, 2019 02;112:67-77.
    PMID: 30389346 DOI: 10.1016/j.peptides.2018.10.009
    A cichlid fish, the Nile tilapia (Oreochromis niloticus), is a maternal mouthbrooder, which exhibits minimum energy expenditure and slower ovarian cycles during mouthbrooding. The objective of this study was to observe changes in the gene expression of key neuropeptides involved in the control of appetite and reproduction, including neuropeptide Y a (NPYa), reproductive neuropeptides: gonadotropin-releasing hormone (GnRH1, GnRH2 and GnRH3) and kisspeptin (Kiss2) during mouthbrooding (4- and 12-days), 12-days of food restriction and 12-days of food restriction followed by refeeding. The food restriction regime showed a significant increase in npya mRNA levels in the telencephalon. However, there were no significant alterations in npya mRNA levels during mouthbrooding. gnrh1 mRNA levels were significantly lower in mouthbrooding female as compared with females with food restriction. gnrh3 mRNA levels were also significantly lower in female with 12-days of mouthbrooding, 12-days of food restriction followed by 12-days of refeeding when compared with controls. There were no significant differences in gnrh2 and kiss2 mRNA levels between groups under different feeding regimes. No significant changes were observed in mRNA levels of receptors for peripheral metabolic signaling molecules: ghrelin (GHS-R1a and GHS-R1b) and leptin (Lep-R). These results suggested that unaffected npya mRNA levels in the telencephalon might contribute to suppression of appetite in mouthbrooding female tilapia. Furthermore, lower gnrh1 and gnrh3 mRNA levels may influence the suppression of reproductive functions such as progression of ovarian cycle and reproductive behaviours, while GnRH2 and Kiss2 may not play a significant roles in reproduction under food restriction condition.
    Matched MeSH terms: Brain/metabolism*
  5. Comparative evaluation of the degree of pegylation of poly(lactic-co-glycolic acid) nanoparticles in enhancing central nervous system delivery of loperamide
    Kirby BP, Pabari R, Chen CN, Al Baharna M, Walsh J, Ramtoola Z
    J Pharm Pharmacol, 2013 Oct;65(10):1473-81.
    PMID: 24028614 DOI: 10.1111/jphp.12125
    In this study, we examined the relative cellular uptake of nanoparticles (NPs) formulated using poly(lactic-co-glycolic acid) (PLGA) polymers with increasing degree of pegylation (PLGA-PEG) and their potential to deliver loperamide to the brain of a mouse.
    Matched MeSH terms: Brain/metabolism*
  6. Chronic and acute ammonia toxicity in mudskippers, Periophthalmodon schlosseri and Boleophthalmus boddaerti: brain ammonia and glutamine contents, and effects of methionine sulfoximine and MK801
    Ip YK, Leong MW, Sim MY, Goh GS, Wong WP, Chew SF
    J Exp Biol, 2005 May;208(Pt 10):1993-2004.
    PMID: 15879078
    The objective of this study was to elucidate if chronic and acute ammonia intoxication in mudskippers, Periophthalmodon schlosseri and Boleophthalmus boddaerti, were associated with high levels of ammonia and/or glutamine in their brains, and if acute ammonia intoxication could be prevented by the administration of methionine sulfoximine [MSO; an inhibitor of glutamine synthetase (GS)] or MK801 [an antagonist of N-methyl D-aspartate type glutamate (NMDA) receptors]. For P. schlosseri and B. boddaerti exposed to sublethal concentrations (100 and 8 mmol l(-1) NH4Cl, respectively, at pH 7.0) of environmental ammonia for 4 days, brain ammonia contents increased drastically during the first 24 h, and they reached 18 and 14.5 micromol g(-1), respectively, at hour 96. Simultaneously, there were increases in brain glutamine contents, but brain glutamate contents were unchanged. Because glutamine accumulated to exceptionally high levels in brains of P. schlosseri (29.8 micromol g(-1)) and B. boddaerti (12.1 micromol g(-1)) without causing death, it can be concluded that these two mudskippers could ameliorate those problems associated with glutamine synthesis and accumulation as observed in patients suffering from hyperammonemia. P. schlosseri and B. boddaerti could tolerate high doses of ammonium acetate (CH3COONH4) injected into their peritoneal cavities, with 24 h LC50 of 15.6 and 12.3 micromol g(-1) fish, respectively. After the injection with a sublethal dose of CH3COONH4 (8 micromol g(-1) fish), there were significant increases in ammonia (5.11 and 8.36 micromol g(-1), respectively) and glutamine (4.22 and 3.54 micromol g(-1), respectively) levels in their brains at hour 0.5, but these levels returned to normal at hour 24. By contrast, for P. schlosseri and B. boddaerti that succumbed within 15-50 min to a dose of CH3COONH4 (15 and 12 micromol g(-1) fish, respectively) close to the LC50 values, the ammonia contents in the brains reached much higher levels (12.8 and 14.9 micromol g(-1), respectively), while the glutamine level remained relatively low (3.93 and 2.67 micromol g(-1), respectively). Thus, glutamine synthesis and accumulation in the brain was not the major cause of death in these two mudskippers confronted with acute ammonia toxicity. Indeed, MSO, at a dosage (100 microg g(-1) fish) protective for rats, did not protect B. boddaerti against acute ammonia toxicity, although it was an inhibitor of GS activities from the brains of both mudskippers. In the case of P. schlosseri, MSO only prolonged the time to death but did not reduce the mortality rate (100%). In addition, MK801 (2 microg g(-1) fish) had no protective effect on P. schlosseri and B. boddaerti injected with a lethal dose of CH3COONH4, indicating that activation of NMDA receptors was not the major cause of death during acute ammonia intoxication. Thus, it can be concluded that there are major differences in mechanisms of chronic and acute ammonia toxicity between brains of these two mudskippers and mammalian brains.
    Matched MeSH terms: Brain/metabolism*
  7. Early-life stress changes expression of GnRH and kisspeptin genes and DNA methylation of GnRH3 promoter in the adult zebrafish brain
    Khor YM, Soga T, Parhar IS
    Gen Comp Endocrinol, 2016 Feb 1;227:84-93.
    PMID: 26686318 DOI: 10.1016/j.ygcen.2015.12.004
    Early-life stress can cause long-term effects in the adulthood such as alterations in behaviour, brain functions and reproduction. DNA methylation is a mechanism of epigenetic change caused by early-life stress. Dexamethasone (DEX) was administered to zebrafish larvae to study its effect on reproductive dysfunction. The level of GnRH2, GnRH3, Kiss1 and Kiss2 mRNAs were measured between different doses of DEX treatment groups in adult zebrafish. Kiss1 and GnRH2 expression were increased in the 200mg/L DEX treated while Kiss2 and GnRH3 mRNA levels were up-regulated in the 2mg/L DEX-treated zebrafish. The up-regulation may be related to programming effect of DEX in the zebrafish larvae, causing overcompensation mechanism to increase the mRNA levels. Furthermore, DEX treatment caused negative impact on the development and maturation of the testes, in particular spermatogenesis. Therefore, immature gonadal development may cause positive feedback by increasing GnRH and Kiss. This indicates that DEX can alter the regulation of GnRH2, GnRH3, Kiss1 and Kiss2 in adult zebrafish, which affects maturation of gonads. Computer analysis of 1.5 kb region upstream of the 5' UTR of Kiss1, Kiss2, GnRH2 and GnRH3 promoter showed that there are putative binding sites of glucocorticoid response element and transcription factors involved in stress response. GnRH3 promoter analysed from pre-optic area, ventral telencephalon and ventral olfactory bulb showed higher methylation at CpG residues located on -1410, -1377 and -1355 between control and 2mg/L DEX-treated groups. Hence, early-life DEX treatment can alter methylation of GnRH3 gene promoter, which subsequently affects gene regulation and reproductive functions.
    Matched MeSH terms: Brain/metabolism*
  8. Proteomic analysis reveals brain Rab35 as a potential biomarker of mitragynine withdrawal in rats
    Hassan R, Othman N, Mansor SM, Müller CP, Hassan Z
    Brain Res Bull, 2021 07;172:139-150.
    PMID: 33901587 DOI: 10.1016/j.brainresbull.2021.04.018
    Mitragyna speciosa, also known as kratom, has been used for mitigating the severity of opioid withdrawal in humans. Its main indole alkaloid, mitragynine, has been considered as a pharmacotherapy for pain conditions and opioid replacement therapy. However, at high doses, chronic mitragynine may also have an addiction potential. The effects of chronic action of mitragynine in the brain are still unknown. The present study developed a mitragynine withdrawal model in rats and used it for a proteomic analysis of mitragynine withdrawal effects. Mitragynine (30 mg/kg, i.p.) was administered daily over a period of 14 days and then withdrawn. A proteomic analysis revealed that from a total of 1524 proteins identified, 31 proteins were upregulated, and 3 proteins were downregulated in the mitragynine withdrawal model. The Rab35 protein expression increased most profoundly in the mitragynine withdrawal group as compared to vehicle group. Therefore, it is proposed that Rab35 in the brain might be considered as a potential biomarker during mitragynine withdrawal and might be valuable target protein in developing new pharmacotherapies in the future.
    Matched MeSH terms: Brain/metabolism*
  9. Neurometabolites Alteration in the Acute Phase of Mild Traumatic Brain Injury (mTBI): An In Vivo Proton Magnetic Resonance Spectroscopy (1H-MRS) Study
    Veeramuthu V, Seow P, Narayanan V, Wong JHD, Tan LK, Hernowo AT, et al.
    Acad Radiol, 2018 09;25(9):1167-1177.
    PMID: 29449141 DOI: 10.1016/j.acra.2018.01.005
    RATIONALE AND OBJECTIVES: Magnetic resonance spectroscopy is a noninvasive imaging technique that allows for reliable assessment of microscopic changes in brain cytoarchitecture, neuronal injuries, and neurochemical changes resultant from traumatic insults. We aimed to evaluate the acute alteration of neurometabolites in complicated and uncomplicated mild traumatic brain injury (mTBI) patients in comparison to control subjects using proton magnetic resonance spectroscopy (1H magnetic resonance spectroscopy).

    MATERIAL AND METHODS: Forty-eight subjects (23 complicated mTBI [cmTBI] patients, 12 uncomplicated mTBI [umTBI] patients, and 13 controls) underwent magnetic resonance imaging scan with additional single voxel spectroscopy sequence. Magnetic resonance imaging scans for patients were done at an average of 10 hours (standard deviation 4.26) post injury. The single voxel spectroscopy adjacent to side of injury and noninjury regions were analysed to obtain absolute concentrations and ratio relative to creatine of the neurometabolites. One-way analysis of variance was performed to compare neurometabolite concentrations of the three groups, and a correlation study was done between the neurometabolite concentration and Glasgow Coma Scale.

    RESULTS: Significant difference was found in ratio of N-acetylaspartate to creatine (NAA/Cr + PCr) (χ2(2) = 0.22, P brain injury. The ratio of NAA and NAAG has potential to serve as a biomarker reflecting injury severity in a quantifiable manner as it discriminates between the complicated and uncomplicated cases of mTBI.

    Matched MeSH terms: Brain/metabolism
  10. Fulltext Delta-9-Tetrahydrocannabinol (∆9-THC) Induce Neurogenesis and Improve Cognitive Performances of Male Sprague Dawley Rats
    Suliman NA, Taib CNM, Moklas MAM, Basir R
    Neurotox Res, 2018 02;33(2):402-411.
    PMID: 28933048 DOI: 10.1007/s12640-017-9806-x
    Neurogenesis is influenced by various external factors such as enriched environments. Some researchers had postulated that neurogenesis has contributed to the hippocampal learning and memory. This project was designed to observe the effect of Delta-9-tetrahydrocannabinol (∆9-THC) in cognitive performance that influenced by the neurogenesis. Different doses of ∆9-THC were used for observing the neurogenesis mechanism occurs in the hippocampus of rats. The brains were stained with antibodies, namely BrdU, glial fibrillary acidic protein (GFAP), nestin, doublecortin (DCX) and class III β-tubulin (TuJ-1). The cognitive test was used novel-object discrimination test (NOD) while the proteins involved, DCX and brain-derived neurotrophic factor (BDNF), were measured. Throughout this study, ∆9-THC enhanced the markers involved in all stages of neurogenesis mechanism. Simultaneously, the cognitive behaviour of rat also showed improvement in learning and memory functions observed in behavioural test and molecular perspective. Administration of ∆9-THC was observed to enhance the neurogenesis in the brain, especially in hippocampus thus improved the cognitive function of rats.
    Matched MeSH terms: Brain/metabolism
  11. siRNA Blocking of Mammalian Target of Rapamycin (mTOR) Attenuates Pathology in Annonacin-Induced Tauopathy in Mice
    Salama M, El-Desouky S, Alsayed A, El-Hussiny M, Magdy K, Fekry E, et al.
    Neurotox Res, 2019 May;35(4):987-992.
    PMID: 30362086 DOI: 10.1007/s12640-018-9974-3
    Tauopathy is a pathological hallmark of many neurodegenerative diseases. It is characterized by abnormal aggregates of pathological phosphotau and somatodendritic redistribution. One suggested strategy for treating tauopathy is to stimulate autophagy, hence, getting rid of these pathological protein aggregates. One key controller of autophagy is mTOR. Since stimulation of mTOR leads to inhibition of autophagy, inhibitors of mTOR will cause stimulation of autophagy process. In this report, tauopathy was induced in mice using annonacin. Blocking of mTOR was achieved through stereotaxic injection of siRNA against mTOR. The behavioral and immunohistochemical evaluation revealed the development of tauopathy model as proven by deterioration of behavioral performance in open field test and significant tau aggregates in annonacin-treated mice. Blocking of mTOR revealed significant clearance of tau aggregates in the injected side; however, tau expression was not affected by mTOR blockage.
    Matched MeSH terms: Brain/metabolism
  12. Propolis ameliorates tumor nerosis factor-α, nitric oxide levels, caspase-3 and nitric oxide synthase activities in kainic acid mediated excitotoxicity in rat brain
    Swamy M, Suhaili D, Sirajudeen KN, Mustapha Z, Govindasamy C
    Afr J Tradit Complement Altern Med, 2014;11(5):48-53.
    PMID: 25395704
    BACKGROUND: Increased nitric oxide (NO), neuronal inflammation and apoptosis have been proposed to be involved in excitotoxicity plays a part in many neurodegenerative diseases. To understand the neuro-protective effects of propolis, activities of Nitric oxide synthase (NOS) and caspase-3 along with NO and tumor necrosis factor-α (TNF-α) levels were studied in cerebral cortex (CC), cerebellum (CB) and brain stem (BS) in rats supplemented with propolis prior to excitotoxic injury with kainic acid (KA).

    MATERIALS AND METHODS: Male Sprague-Dawley rats were divided into four groups (n=6 rats per group) as Control, KA, Propolis and KA+Propolis. The control group and KA group have received vehicle and saline. Propolis group and propolis + KA group were orally administered with propolis (150 mg/kg body weight), five times every 12 hours. KA group and propolis +KA group were injected subcutaneously with kainic acid (15 mg/kg body weight) and were sacrificed after 2 hrs. CC, CB and BS were separated, homogenized and used for estimation of NOS, caspase-3, NO and TNF-α by commercial kits. Results were analyzed by one way ANOVA, reported as mean + SD (n=6 rats), and p<0.05 was considered statistically significant.

    RESULTS: The concentration of NO, TNF-α, NOS and caspase-3 activity were increased significantly (p<0.001) in all the three brain regions tested in KA group compared to the control. Propolis supplementation significantly (p<0.001) prevented the increase in NOS, NO, TNF-α and caspase-3 due to KA.

    CONCLUSION: Results of this study clearly demonstrated that the propolis supplementation attenuated the NOS, caspase-3 activities, NO, and TNF-α concentration and in KA mediated excitotoxicity. Hence propolis can be a possible potential protective agent against excitotoxicity and neurodegenerative disorders.

    Matched MeSH terms: Brain/metabolism
  13. Fulltext Functional transcriptome analysis of the postnatal brain of the Ts1Cje mouse model for Down syndrome reveals global disruption of interferon-related molecular networks
    Ling KH, Hewitt CA, Tan KL, Cheah PS, Vidyadaran S, Lai MI, et al.
    BMC Genomics, 2014;15:624.
    PMID: 25052193 DOI: 10.1186/1471-2164-15-624
    The Ts1Cje mouse model of Down syndrome (DS) has partial triplication of mouse chromosome 16 (MMU16), which is partially homologous to human chromosome 21. These mice develop various neuropathological features identified in DS individuals. We analysed the effect of partial triplication of the MMU16 segment on global gene expression in the cerebral cortex, cerebellum and hippocampus of Ts1Cje mice at 4 time-points: postnatal day (P)1, P15, P30 and P84.
    Matched MeSH terms: Brain/metabolism*
  14. Anxiolytic-like effects of mitragynine in the open-field and elevated plus-maze tests in rats
    Hazim AI, Ramanathan S, Parthasarathy S, Muzaimi M, Mansor SM
    J Physiol Sci, 2014 May;64(3):161-9.
    PMID: 24464759 DOI: 10.1007/s12576-014-0304-0
    The effects of mitragynine on anxiety-related behaviours in the open-field and elevated plus-maze tests were evaluated. Male Sprague-Dawley rats were orally treated with mitragynine (10, 20 and 40 mg/kg) or diazepam (10 mg/kg) 60 min before behavioural testing. Mitragynine doses used in this study were selected on the basis of approximately human equivalent doses with reference to our previous literature reports. Acute administration of mitragynine (10, 20 and 40 mg/kg) or diazepam (10 mg/kg) increased central zone and open arms exploration in the open-field and elevated plus-maze tests respectively. These anxiolytic-like effects of mitragynine were effectively antagonized by intraperitoneal administration of naloxone (2 mg/kg), flumazenil (10 mg/kg), sulpiride (0.5 mg/kg) or SCH 23390 (0.02 mg/kg) 15 min before mitragynine treatments. These findings reveal that the acute administration of mitragynine produces anxiolytic-like effects and this could be possibly attributed to the interactions among opioidergic, GABAergic and dopaminergic systems in brain regions involved in anxiety.
    Matched MeSH terms: Brain/metabolism
  15. Caffeic acid protects tissue antioxidants and DNA content in methamphetamine induced tissue toxicity in Sprague Dawley rats
    Koriem KM, Abdelhamid AZ, Younes HF
    Toxicol. Mech. Methods, 2013 Feb;23(2):134-43.
    PMID: 22992185 DOI: 10.3109/15376516.2012.730561
    Caffeic acid (CA) (3,4-dihydroxycinnamic acid) is among the major hydroxycinnamic acids. Hydroxycinnamic acid is the major subgroup of phenolic compounds. Methamphetamine (METH) is a potent addictive psychostimulant. Chronic use and acute METH intoxication can cause substantial medical consequences, including spleen, kidney, liver and heart. The objective of the present study was to evaluate the antioxidant activity of CA to protect against oxidative stress and DNA damage to various organs in METH toxicity. Thirty-two male Sprague Dawley (SD) rats were divided into four equal groups: group 1 was injected (i.p) with saline (1 mL/kg) while groups 2,3 and 4 were injected (i.p) with METH (10 mg/kg) twice a day over five days period. Where 100 & 200 mg/kg of CA were injected (i.p) into groups 3 and 4, respectively one day before exposure to METH injections. Tissue antioxidants and DNA content were evaluated in different tissues. METH decreased glutathione (GSH) and glutathione peroxidase (GPx) levels while increased malondialdehyde (MDA), catalase (CAT) and protein carbonyl levels in brain (hypothalamus), liver, and kidney tissues of rats. METH increased hyperdiploidy in these tissues and DNA damage results. Prior treatment of CA to animals exposed to METH restores the above parameters to the normal levels and preserves the DNA content of these tissues. These results were supported by histopathological investigations. In conclusion, METH induced oxidative stress and DNA damage and pretreatment of CA before METH injections prevented tissue oxidative stress and DNA damage in METH-treated animals.
    Matched MeSH terms: Brain/metabolism
  16. Synthesis of α-hydroxyphosphonates and their antioxidant properties
    Naidu KR, Kumar KS, Arulselvan P, Reddy CB, Lasekan O
    Arch Pharm (Weinheim), 2012 Dec;345(12):957-63.
    PMID: 23015406 DOI: 10.1002/ardp.201200192
    A series of α-hydroxyphosphonates were synthesized from the reaction of aldehyde (1) with triethylphosphite (2) in the presence of oxone and evaluated for their antioxidant properties against lipid peroxidation, reduced glutathione, superoxide dismutase, and catalase. The majority of the compounds showed promising antioxidant activity. Diethyl anthracen-9-yl (hydroxy) methylphosphonate (3n) is the most potent and biologically active compound against free radicals.
    Matched MeSH terms: Brain/metabolism
  17. Habenular Kiss1 neurons modulate the serotonergic system in the brain of zebrafish
    Ogawa S, Ng KW, Ramadasan PN, Nathan FM, Parhar IS
    Endocrinology, 2012 May;153(5):2398-407.
    PMID: 22454151 DOI: 10.1210/en.2012-1062
    The Kiss1/KISS1 gene has recently been implicated as a potent hypothalamic regulator of reproductive functions, in particular, the onset of puberty in mammals. In zebrafish (Danio rerio), there are two kiss1 homologues (kiss1 and kiss2) expressed in the brain: Kiss2-expressing neurons in the hypothalamic nuclei are considered potent regulators of reproduction, whereas the role of Kiss1-expressing neurons in the habenula remains unknown. We first analyzed the expression of kiss1 mRNA in a transgenic zebrafish, in which the habenula-interpeduncular nucleus (IPN) pathway is labelled with green fluorescent protein, and our application of a biocytin neural tracer into the habenula showed the presence of neuronal projections of Kiss1 neurons to the ventral IPN. Therefore, we speculated that kiss1 neurons might regulate the serotonergic system in the raphe. However, laser microdissection followed by real-time PCR revealed the expression of Kiss1 receptor (kissr1) mRNA in the habenula and the ventral IPN but not in the dorsal IPN or the serotonergic neurons in the raphe nuclei. Dual-fluorescent in situ hybridization revealed the coexpression of kiss1 and kissr1 mRNA in the habenula. Administration of Kiss1 significantly decreased the level of kiss1 mRNA (0.3- to 0.5-fold, P < 0.001), but the level of c-fos mRNA was increased (≈ 3-fold, P < 0.05) in the ventral habenula, suggesting that there is autocrine regulation of the kiss1 gene. Kiss1 administration significantly increased the c-fos mRNA levels in the raphe nuclei (2.5-fold, P < 0.001) and genes involved in the regulation of serotonin levels (pet1 and slc6a4a; 3.3- and 2.2-fold, P < 0.01). These findings suggest that the autocrine-regulated habenular Kiss1 neurons indirectly regulate the serotonergic system in the raphe nuclei through the IPN in the zebrafish.
    Matched MeSH terms: Brain/metabolism*
  18. Disposition and tissue distribution of imatinib in a liposome formulation after intravenous bolus dose to mice
    Moo KS, Radhakrishnan S, Teoh M, Narayanan P, Bukhari NI, Segarra I
    Yao Xue Xue Bao, 2010 Jul;45(7):901-8.
    PMID: 20931790
    Imatinib is an efficacious anticancer drug with a spectrum of potential antitumour applications limited by poor biodistribution at therapeutic concentrations to the tissues of interest. We assess the pharmacokinetic and tissue distribution profile of imatinib in a liposome formulation. Its single dose (6.25 mg x kg(-1)) in a liposome formulation was administered iv to male mice. Imatinib concentration was measured in plasma, spleen, liver, kidney and brain using a HPLC assay. Non-compartmental pharmacokinetic approach was used to assess the disposition parameters. The plasma disposition profile was biphasic with a plateau-like second phase. The AUC(0-->infinity) was 11.24 microg x h x mL(-1), the elimination rate constant (k(el)) was 0.348 h(-1) and the elimination half life (t(1/2)) was 2.0 h. The mean residence time (MRT) was 2.59 h, V(SS) was 1.44 L x kg(-1) and clearance was 0.56 L x h x kg(-1). Liver achieved the highest tissue exposure: CMAX = 18.72 microg x mL(-1); AUC(0-->infinity)= 58.18 microg x h x mL(-1) and longest t(1/2) (4.29 h) and MRT (5.31 h). Kidney and spleen AUC(0-->infinity) were 47.98 microg x h x mL(-1) and 23.46 microg x h x mL(-1), respectively. Half-life was 1.83 h for the kidney and 3.37 h for the spleen. Imatinib penetrated into the brain reaching approximately 1 microg x g(-1). Upon correction by organ blood flow the spleen showed the largest uptake efficiency. Liposomal imatinib presented extensive biodistribution. The drug uptake kinetics showed mechanism differences amongst the tissues. These findings encourage the development of novel imatinib formulations to treat other cancers.
    Matched MeSH terms: Brain/metabolism
  19. Investigation of highly unsaturated fatty acid metabolism in the Asian sea bass, Lates calcarifer
    Mohd-Yusof NY, Monroig O, Mohd-Adnan A, Wan KL, Tocher DR
    Fish Physiol Biochem, 2010 Dec;36(4):827-43.
    PMID: 20532815 DOI: 10.1007/s10695-010-9409-4
    Lates calcarifer, commonly known as the Asian sea bass or barramundi, is an interesting species that has great aquaculture potential in Asia including Malaysia and also Australia. We have investigated essential fatty acid metabolism in this species, focusing on the endogenous highly unsaturated fatty acid (HUFA) synthesis pathway using both biochemical and molecular biological approaches. Fatty acyl desaturase (Fad) and elongase (Elovl) cDNAs were cloned and functional characterization identified them as ∆6 Fad and Elovl5 elongase enzymes, respectively. The ∆6 Fad was equally active toward 18:3n-3 and 18:2n-6, and Elovl5 exhibited elongation activity for C18-20 and C20-22 elongation and a trace of C22-24 activity. The tissue profile of gene expression for ∆6 fad and elovl5 genes, showed brain to have the highest expression of both genes compared to all other tissues. The results of tissue fatty acid analysis showed that the brain contained more docosahexaenoic acid (DHA, 22:6n-3) than flesh, liver and intestine. The HUFA synthesis activity in isolated hepatocytes and enterocytes using [1-(14)C]18:3n-3 as substrate was very low with the only desaturated product detected being 18:4n-3. These findings indicate that L. calcarifer display an essential fatty acid pattern similar to other marine fish in that they appear unable to synthesize HUFA from C18 substrates. High expression of ∆6 fad and elovl5 genes in brain may indicate a role for these enzymes in maintaining high DHA levels in neural tissues through conversion of 20:5n-3.
    Matched MeSH terms: Brain/metabolism*
  20. Nitric oxide (NO), citrulline-NO cycle enzymes, glutamine synthetase, and oxidative status in kainic acid-mediated excitotoxicity in rat brain
    Swamy M, Sirajudeen KN, Chandran G
    Drug Chem Toxicol, 2009;32(4):326-31.
    PMID: 19793024 DOI: 10.1080/01480540903130641
    Neuronal excitation, involving the excitatory glutamate receptors, is recognized as an important underlying mechanism in neurodegenerative disorders. To understand their role in excitotoxicity, the nitric oxide synthase (NOS), argininosuccinate synthetase (AS), argininosuccinate lyase (AL), glutamine synthetase (GS), and arginase activities, along with the concentration of nitrate/nitrite, thiobarbituric acid-reactive substances (TBARS), and total antioxidant status (TAS), were estimated in the cerebral cortex, cerebellum, and brain stem of rats subjected to kainic acid-mediated excitotoxicity. The results of this study clearly demonstrated the increased production of NO by increased activity of NOS. The increased activities of AS and AL suggest the increased and effective recycling of citrulline to arginine in excitotoxicity, making NO production more effective and contributing to its toxic effects. The decreased activity of GS may favor the prolonged availability of glutamic acid, causing excitotoxicity, leading to neuronal damage. The increased formation of TBARS and decreased TAS indicate the presence of oxidative stress in excitotoxicity.
    Matched MeSH terms: Brain/metabolism
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